Despite the rocky relationship between Tesla and the NTSB, agency spokesperson Keith Holloway said he's still uncertain as to whether the agency will open an investigation into the accident.
Schwall, "who was the organization's principle specialized contact with U.S. wellbeing agents, has left for match Waymo LLC, as per individuals acquainted with the choice", The Wall Street Journal wrote about Sunday.
News of the crash came as a top Tesla official who had been the main technical contact with USA safety investigators left the company to join rival Waymo.
Musk said in Monday's email Tesla would still rapidly hire people to fill critical positions "to support the Model 3 production ramp and future product development".
On 2 May Musk said Tesla would conduct "a reorganisation restructuring" during May, without providing more details.
He added: The number of sort of third-party contracting companies that we're using has really gotten out of control, so we're going to scrub the barnacles on that front.
Investors gave Mr Musk some rare criticism after the call in which he referred to one analyst as a boring bonehead.
Police in a Salt Lake City suburb say it's not immediately known whether a Tesla Model S sedan's semi-autonomous Autopilot driving system was in use when it rear-ended a truck apparently without braking before impact at approximately 60 miles per hour.
Witnesses said the Tesla auto did not brake prior to impact, the police said in a statement, adding it was unknown if the autopilot feature in the Model S was engaged at the time.
The driver of the fire department vehicle suffered minor whiplash and was not taken to a hospital.
In another Twitter message on Monday, Musk said the "probability of fatality is much lower in a Tesla", saying Tesla would begin reporting safety numbers from the second quarter of 2018.
"We've been doing a thorough search of our service records, and we can not find anything suggesting that the customer ever complained to Tesla about the performance of Autopilot", Tesla said in a statement.
The 48-year-old died when his Tesla caught fire after he slammed into a crash barrier on the A2 motorway in southern Ticino.
Police said they had been in contact with the National Transportation Safety Board about the crash.